I am not sure of its exact name I just had someone show me it on his truck and said it needed to be added if you added 2" of lift to the front not to throw the axle alignment off. I questioned that because it does not seem as it would but im no expert, i was going to throw in 2" lift blocks for the time being until I decide on what size lift I wanted in the future. Would the 2" lift blocks work just as good as the add a leafs?